KANSAS- COMPACT COMMISSION ENGINEERING COMMITTEE REPORT July 28, 2021 Oklahoma Water Resources Board Oklahoma City, OK

This report covers water year (WY) 2020: October 1, 2019 through September 30, 2020. The report contains the standard updates to streamflow data, water quality data and reservoir conservation storage capacities constructed in the Compact area.

WY2020 mean flows at four of the five Oklahoma gaging stations were lower than WY2019 mean flows. At the Cimarron River gage near Waynoka, OK, the WY2020 mean flow was 115 cfs, an 81% decrease from the WY2019 mean flow of 607 cfs. Three of the other Oklahoma gaging stations reported decreases in mean flow ranging from 42% to 70% between WY2019 and WY2020. Due to a bridge reconstruction project, the fifth Oklahoma gaging station – the gage near Blackwell, OK – was not in operation from April 2, 2020 through the end of the water year.

The Verdigris River gage at Independence, KS reported a 51% decrease in mean flow, from 6,302 cfs in WY2019 to 3,080 cfs in WY2020. The Arkansas River gage at Arkansas City, KS reported a 76% decrease in mean flow, from 6,962 cfs in WY2019 to 1,655 cfs in WY2020.

WY2020 mean flows at the gaging stations in and Oklahoma varied in relation to the historical mean flows at those gaging stations, ranging from a 57% decrease at the Cimarron River gage near Waynoka, OK to a 36% increase at the Verdigris River gage near Independence, KS.

The Engineering Committee reports that there were no new water storage structures completed in the Kansas or Oklahoma Compact areas between October 1, 2019 and September 30, 2020 that exceeded the 100-acre-foot conservation storage minimum requirement as set forth in the Compact.

Respectfully submitted by the Engineering Committee:

______Elizabeth Hickman, Member

______Yohanes Sugeng, Member

Water Flow Data Water Year 2020 Oklahoma and Kansas

Mean Flow, Mean Mean Years Period of Flow, Flow, of Record WY2019 WY2020 Station Description Record (cfs) (cfs) (cfs)

07175500 Caney River near Ramona, OK 37 1578 3289 1894

07152000 Chikaskia River near Blackwell, OK 83 622 2076 ----

07158000 Cimarron River near Waynoka, OK 83 266 607 115

07185000 Neosho River near Commerce, OK 81 3887 11070 4533

07151000 at Tonkawa, OK 79 929 3138 947

07170500 Verdigris River at Independence, KS 53 2267 6302 3080

07146500 Arkansas River at Arkansas City, KS 101 1989 6962 1655 Source: Geological Survey, National Water Information System – waterdata.usgs.gov.

Water Quality Data Fall 2019 through Fall 2020 Stations in Kansas

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(mg/L) (mg/L)

Hardness (µOhms/cm)

Station Station ecificConductance

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WaterTemperature S Number Description Dissolved Total Solids Min Max Min Max Min Max Min Max 000215 Verdigris River near Coffeyville 170 300 140 250 300 540 6 31 Arkansas River near Arkansas 000218 City 460 1020 160 350 770 1700 4 32 000529 Chikaskia River near Corbin 640 400 230 280 610 670 4 29 000566 Neosho River near Oswego 140 320 97 260 240 570 6 30 000214 Neosho River near Chetopa 140 330 95 270 230 570 6 28 Source: Kansas Department of Health and Environment, Stream Chemistry Monitoring Program, July 21, 2021.